My i5 750 is hungry as f*ck

[backpack]

I previously had it running 3.6GHz with decent volts/temps with a 212+ HSF

Now I've moved onto a watercooling loop and trying for 4ghz
Isolated the baseclock to 200MHz with 1.23 VTT
Then did my RAM over night with memtest+. 0 errors

Set my multi back up to 20x and started the climb of voltage and baseclock (followed Miahallen's guide)

Got to 3.8GHz but it took 1.3750 vcore

Then going from that to 4GHz I needed to keep notching the voltage up to 1.45vcore lol

Just failed after 1h 58m 23s OCCT

Temps haven't gone over 49.

Any tips?
It'd be greatly appreciated!